Got HTTP status 404 Not Found for "http://john-chambers.us/~jc/music/book/JamesOswald/CPC/21361_Drunken_Magg_Young.abc/all"
pngcmd="(./ps2png 512 512 /Users/jc/w/tmp/Tune-3429-all.ps) >>/Users/jc/w/tmp/Tune-3429-get.log 2>&1" returned status 256
http://john-chambers.us/~jc/music/book/JamesOswald/CPC/21361_Drunken_Magg_Young.abc/all

Error exit status 256; here are some files to check:
[get.cgi V=1/1 B=0 scale=0.55 512x512 PNG]
filesizedescription
Coll_3429.log 450010 Log file, useful mostly for debugging
Coll_34291.log 919616 Log file, useful mostly for debugging
Coll_34293.log 458410 Log file, useful mostly for debugging
Coll_34299.log 462609 Log file, useful mostly for debugging
Form_34294.log 966 Log file, useful mostly for debugging
Tune-3429-all.abc 176 ABC music file with the extracted tune(s)
Tune-3429-all.ps 6 PostScript
Tune-3429-all.txt 176 Plain-text file with the extracted tune(s)
Tune-3429-get.log 9099 Log file, useful mostly for debugging
Tune-34290-get.log 3546 Log file, useful mostly for debugging
Tune-34296-get.log 5102 Log file, useful mostly for debugging
Tune-34297-get.log 5846 Log file, useful mostly for debugging
These files should be available for 24 hours.